This invention relates to a method of texturing the surface of a glass substrate for a magnetic disk.
The substrate of a magnetic disk has its surface mirror-polished first and then has it textured so as to have a specified surface roughness. The purpose of texturing is to form line marks on the substrate surface such that when it is used with a magnetic head, the floating distance of the magnetic head from the disk surface can be maintained dependably constant while the disk is rotating at a fast rate and also such that the magnetic head can be prevented from becoming adsorbed to the disk surface while the disk is stationary.
The texturing is usually carried out by supplying a suspension mixed with minute abrasive particles of diamond or alumina to the surface of the substrate while the latter is rubbed with a woven or unwoven tape or a tape with planted hairs. Textured line marks can thus be formed as these abrading particles are pressed on and rubbed against the substrate surface to mechanically grind it. Such a process for forming line marks is usually referred to as the chemical mechanical texturing.
Recently, glass substrates are coming to be used as commonly as substrates made of an aluminum alloy for producing magnetic disks, and these glass substrates are also required to have their surface or surfaces textured for the same reasons, that is, such that the floating distance of the magnetic head can be reduced and hence that the recording density of the magnetic disks as memory media can be increased.
Since glass substrates are hard, however, it has been considered difficult to form sufficiently minute and uniform line marks on a glass substrate by a mechanical texturing process.